A. Field of Invention
This invention pertains to a corrosion prevention system and method of producing the same, and more specifically to a system for protecting a metal substrate from corrosion utilizing a cathodic coating comprising at least one inherently conductive polymer and sacrificial metal particles.
B. Description of the Related Art
One type of coating used to protect metals from corrosion is called a barrier coating. Barrier coatings function to separate the metal from the surrounding environment. Some examples of barrier coatings include paints and nickel and chrome plating. However, as with all barrier coatings, holidays in the barrier coatings leave the metal substrate susceptible to corrosion. Electrochemically active barrier coatings, such as nickel, chrome, and conductive polymer layers, can actually accelerate corrosion of underlying metals at holidays in the coating.
Another type of coating used to protect metal substrates is called sacrificial coatings. The metal substrate is coated with a material that reacts with the environment and is consumed in preference to the substrate it protects. These coatings may be further subdivided into chemically reactive, e.g., chromate coatings, and electrochemically active, or galvanically active, e.g., aluminum, cadmium, magnesium, and zinc. The galvanically active coatings must be conductive and are commonly called cathodic protection.
In the art, a major difficulty has been the creation of a coating that protects like a cathodic system but is applied with the ease of a typical barrier coating system. Furthermore, there are many environmental drawbacks with both traditional barrier and sacrificial methods, from use of high levels of volatile organic compounds to expensive treatment of waste waters produced by plating and subsequent surface preparation for top-coating processes.
The present invention contemplates a new and improved coating system and method of producing the same which overcomes the foregoing difficulties and others while providing better and more advantageous overall results.